1. Field of the Invention
The present invention relates to a full-color organic light emitting display (OLED) and method of fabricating the same, the display having an encapsulation substrate that includes a color modification layer having moisture absorbent materials, the color modification layer being either a color filter layer or a color change medium.
2. Description of the Related Art
In general, an OLED includes a substrate, an anode disposed on the substrate, an emission layer disposed on the anode, a cathode disposed on the emission layer, and an encapsulation substrate. In such an OLED, once a voltage is applied between the anode and the cathode, holes and electrons are injected into the emission layer. The holes and electrons are recombined in the emission layer to generate excitons. When the excitons change from an exited state to a ground state, light is emitted.
In order to realize a full-color OLED, respective emission layers corresponding to red (R), green (G), and blue (B) colors can be formed. However, since the respective emission layers corresponding to red (R), green (G), and blue (B) colors have life spans different from one another, it is difficult to keep white balance after the OLED is driven for a long time. In addition, because of a technical limit for forming fine patterns in each pixel, it is difficult to fabricate high-resolution display devices.
To solve these problems, a new method of fabricating a full-color OLED was proposed. The method includes forming an emission layer that emits light of a single color, and forming a color filter layer that extracts light of a predetermined color from the light emitted by the emission layer. Instead of a color filter layer, a color conversion layer that converts the light emitted by the emission layer into light of a predetermined color can be used. As an example, U.S. Pat. No. 6,522,066 to Sheu et al includes an emission layer emitting blue light and a color conversion layer formed using photolithography.
Meanwhile, in the OLED, an encapsulation substrate is attached to a substrate such that an anode, an emission layer, and a cathode formed on the substrate are protected. However, I have found that such a structure deteriorates quickly because moisture and oxygen tend to destroy the emission layer. Therefore, what is needed is an improved design for an OLED and an improved method of making the same where the emission layer can be protected from moisture and oxygen.